IIB   20738
INSTITUTO DE INVESTIGACIONES BIOLOGICAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Internalization of an extracellular protein during early seed imbibition?
Autor/es:
PAGNUSSAT, L.; PINEDO, M. L.; LOMBARDO, C.; LAURA DE LA CANAL
Lugar:
Mérida, Mejico
Reunión:
Congreso; Annual Meeting American Society of Plant Biologists; 2008
Resumen:
Internalization of an extracellular protein during early seed  imbibition? L. Pagnussat, M. Pinedo, C. Lombardo, L. de la Canal   Lipid transfer proteins (LTPs) are recognized as extracellular proteins and synthesized as precursors bearing a signal peptide. We have characterized a LTP present in sunflower dry seeds (Ha-AP10). This protein was only observed in the apoplastic fraction of cotyledons, and particularly concentrated in the epidermis. However, fluorimmunolocalization studies showed that upon imbibition the protein is found both extra- and intracelullarly. Kinetic studies revealed that after 20 min of imbibition Ha-AP10 was already detected inside the cells, probably associated to oil bodies as colocalization with oleosin was observed. The fact that imbibition in the presence of the protein synthesis inhibitor cycloheximide do not change this pattern, suggests that the protein found inside the cells is not a product of de novo synthesis. On the other hand, imbibition in the presence of pharmacological agents affecting vesicular trafficking and fusion events altered the pattern of Ha-AP10, indicating that endocytic pathway may be involved in the internalization of this LTP. These results suggest that Ha-AP10 may be internalized from the extracellular compartment during sunflower seed imbibition and highlights a putative role of endocytosis in early germination to relocalize preformed proteins.